blob: 3ce7bc373a52b7463a156e8ee580851e5afc6a88 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/swap.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
Simon Arlott183ff222007-10-20 01:27:18 +02008 * This file contains the default values for the operation of the
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * Linux VM subsystem. Fine-tuning documentation can be found in
10 * Documentation/sysctl/vm.txt.
11 * Started 18.12.91
12 * Swap aging added 23.2.95, Stephen Tweedie.
13 * Buffermem limits added 12.3.98, Rik van Riel.
14 */
15
16#include <linux/mm.h>
17#include <linux/sched.h>
18#include <linux/kernel_stat.h>
19#include <linux/swap.h>
20#include <linux/mman.h>
21#include <linux/pagemap.h>
22#include <linux/pagevec.h>
23#include <linux/init.h>
24#include <linux/module.h>
25#include <linux/mm_inline.h>
26#include <linux/buffer_head.h> /* for try_to_release_page() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/percpu_counter.h>
28#include <linux/percpu.h>
29#include <linux/cpu.h>
30#include <linux/notifier.h>
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -070031#include <linux/backing-dev.h>
Balbir Singh66e17072008-02-07 00:13:56 -080032#include <linux/memcontrol.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090033#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Lee Schermerhorn64d65192008-10-18 20:26:52 -070035#include "internal.h"
36
Linus Torvalds1da177e2005-04-16 15:20:36 -070037/* How many pages do we try to swap or page in/out together? */
38int page_cluster;
39
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -070040static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
Vegard Nossumf84f95042008-07-23 21:28:14 -070041static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -070042
Adrian Bunkb2213852006-09-25 23:31:02 -070043/*
44 * This path almost never happens for VM activity - pages are normally
45 * freed via pagevecs. But it gets used by networking.
46 */
Harvey Harrison920c7a52008-02-04 22:29:26 -080047static void __page_cache_release(struct page *page)
Adrian Bunkb2213852006-09-25 23:31:02 -070048{
49 if (PageLRU(page)) {
50 unsigned long flags;
51 struct zone *zone = page_zone(page);
52
53 spin_lock_irqsave(&zone->lru_lock, flags);
54 VM_BUG_ON(!PageLRU(page));
55 __ClearPageLRU(page);
56 del_page_from_lru(zone, page);
57 spin_unlock_irqrestore(&zone->lru_lock, flags);
58 }
Li Hongfc916682010-03-05 13:41:54 -080059 free_hot_cold_page(page, 0);
Adrian Bunkb2213852006-09-25 23:31:02 -070060}
61
Nick Piggin8519fb32006-02-07 12:58:52 -080062static void put_compound_page(struct page *page)
63{
Christoph Lameterd85f3382007-05-06 14:49:39 -070064 page = compound_head(page);
Nick Piggin8519fb32006-02-07 12:58:52 -080065 if (put_page_testzero(page)) {
Andy Whitcroft33f2ef82006-12-06 20:33:32 -080066 compound_page_dtor *dtor;
Nick Piggin8519fb32006-02-07 12:58:52 -080067
Andy Whitcroft33f2ef82006-12-06 20:33:32 -080068 dtor = get_compound_page_dtor(page);
Nick Piggin8519fb32006-02-07 12:58:52 -080069 (*dtor)(page);
70 }
71}
72
Linus Torvalds1da177e2005-04-16 15:20:36 -070073void put_page(struct page *page)
74{
Nick Piggin8519fb32006-02-07 12:58:52 -080075 if (unlikely(PageCompound(page)))
76 put_compound_page(page);
77 else if (put_page_testzero(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 __page_cache_release(page);
79}
80EXPORT_SYMBOL(put_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -070082/**
Randy Dunlap76824862008-03-19 17:00:40 -070083 * put_pages_list() - release a list of pages
84 * @pages: list of pages threaded on page->lru
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -070085 *
86 * Release a list of pages which are strung together on page.lru. Currently
87 * used by read_cache_pages() and related error recovery code.
Alexander Zarochentsev1d7ea732006-08-13 23:24:27 -070088 */
89void put_pages_list(struct list_head *pages)
90{
91 while (!list_empty(pages)) {
92 struct page *victim;
93
94 victim = list_entry(pages->prev, struct page, lru);
95 list_del(&victim->lru);
96 page_cache_release(victim);
97 }
98}
99EXPORT_SYMBOL(put_pages_list);
100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101/*
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700102 * pagevec_move_tail() must be called with IRQ disabled.
103 * Otherwise this may cause nasty races.
104 */
105static void pagevec_move_tail(struct pagevec *pvec)
106{
107 int i;
108 int pgmoved = 0;
109 struct zone *zone = NULL;
110
111 for (i = 0; i < pagevec_count(pvec); i++) {
112 struct page *page = pvec->pages[i];
113 struct zone *pagezone = page_zone(page);
114
115 if (pagezone != zone) {
116 if (zone)
117 spin_unlock(&zone->lru_lock);
118 zone = pagezone;
119 spin_lock(&zone->lru_lock);
120 }
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700121 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
Johannes Weiner401a8e12009-09-21 17:02:58 -0700122 int lru = page_lru_base_type(page);
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700123 list_move_tail(&page->lru, &zone->lru[lru].list);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700124 pgmoved++;
125 }
126 }
127 if (zone)
128 spin_unlock(&zone->lru_lock);
129 __count_vm_events(PGROTATED, pgmoved);
130 release_pages(pvec->pages, pvec->nr, pvec->cold);
131 pagevec_reinit(pvec);
132}
133
134/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 * Writeback is about to end against a page which has been marked for immediate
136 * reclaim. If it still appears to be reclaimable, move it to the tail of the
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700137 * inactive list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 */
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700139void rotate_reclaimable_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140{
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700141 if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700142 !PageUnevictable(page) && PageLRU(page)) {
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700143 struct pagevec *pvec;
144 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Miklos Szerediac6aadb2008-04-28 02:12:38 -0700146 page_cache_get(page);
147 local_irq_save(flags);
148 pvec = &__get_cpu_var(lru_rotate_pvecs);
149 if (!pagevec_add(pvec, page))
150 pagevec_move_tail(pvec);
151 local_irq_restore(flags);
152 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800155static void update_page_reclaim_stat(struct zone *zone, struct page *page,
156 int file, int rotated)
157{
158 struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat;
159 struct zone_reclaim_stat *memcg_reclaim_stat;
160
161 memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page);
162
163 reclaim_stat->recent_scanned[file]++;
164 if (rotated)
165 reclaim_stat->recent_rotated[file]++;
166
167 if (!memcg_reclaim_stat)
168 return;
169
170 memcg_reclaim_stat->recent_scanned[file]++;
171 if (rotated)
172 memcg_reclaim_stat->recent_rotated[file]++;
173}
174
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175/*
176 * FIXME: speed this up?
177 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800178void activate_page(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179{
180 struct zone *zone = page_zone(page);
181
182 spin_lock_irq(&zone->lru_lock);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700183 if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700184 int file = page_is_file_cache(page);
Johannes Weiner401a8e12009-09-21 17:02:58 -0700185 int lru = page_lru_base_type(page);
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700186 del_page_from_lru_list(zone, page, lru);
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 SetPageActive(page);
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700189 lru += LRU_ACTIVE;
190 add_page_to_lru_list(zone, page, lru);
Christoph Lameterf8891e52006-06-30 01:55:45 -0700191 __count_vm_event(PGACTIVATE);
Rik van Riel4f98a2f2008-10-18 20:26:32 -0700192
Johannes Weiner6c0b1352009-09-21 17:02:59 -0700193 update_page_reclaim_stat(zone, page, file, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 }
195 spin_unlock_irq(&zone->lru_lock);
196}
197
198/*
199 * Mark a page as having seen activity.
200 *
201 * inactive,unreferenced -> inactive,referenced
202 * inactive,referenced -> active,unreferenced
203 * active,unreferenced -> active,referenced
204 */
Harvey Harrison920c7a52008-02-04 22:29:26 -0800205void mark_page_accessed(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700207 if (!PageActive(page) && !PageUnevictable(page) &&
208 PageReferenced(page) && PageLRU(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 activate_page(page);
210 ClearPageReferenced(page);
211 } else if (!PageReferenced(page)) {
212 SetPageReferenced(page);
213 }
214}
215
216EXPORT_SYMBOL(mark_page_accessed);
217
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700218void __lru_cache_add(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700220 struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
222 page_cache_get(page);
223 if (!pagevec_add(pvec, page))
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700224 ____pagevec_lru_add(pvec, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 put_cpu_var(lru_add_pvecs);
226}
Miklos Szeredi47846b02010-05-25 15:06:06 +0200227EXPORT_SYMBOL(__lru_cache_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700229/**
230 * lru_cache_add_lru - add a page to a page list
231 * @page: the page to be added to the LRU.
232 * @lru: the LRU list to which the page is added.
233 */
234void lru_cache_add_lru(struct page *page, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700236 if (PageActive(page)) {
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700237 VM_BUG_ON(PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700238 ClearPageActive(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700239 } else if (PageUnevictable(page)) {
240 VM_BUG_ON(PageActive(page));
241 ClearPageUnevictable(page);
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700242 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700244 VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page));
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700245 __lru_cache_add(page, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246}
247
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700248/**
249 * add_page_to_unevictable_list - add a page to the unevictable list
250 * @page: the page to be added to the unevictable list
251 *
252 * Add page directly to its zone's unevictable list. To avoid races with
253 * tasks that might be making the page evictable, through eg. munlock,
254 * munmap or exit, while it's not on the lru, we want to add the page
255 * while it's locked or otherwise "invisible" to other tasks. This is
256 * difficult to do when using the pagevec cache, so bypass that.
257 */
258void add_page_to_unevictable_list(struct page *page)
259{
260 struct zone *zone = page_zone(page);
261
262 spin_lock_irq(&zone->lru_lock);
263 SetPageUnevictable(page);
264 SetPageLRU(page);
265 add_page_to_lru_list(zone, page, LRU_UNEVICTABLE);
266 spin_unlock_irq(&zone->lru_lock);
267}
268
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700269/*
270 * Drain pages out of the cpu's pagevecs.
271 * Either "cpu" is the current CPU, and preemption has already been
272 * disabled; or "cpu" is being hot-unplugged, and is already dead.
273 */
274static void drain_cpu_pagevecs(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275{
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700276 struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700277 struct pagevec *pvec;
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700278 int lru;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700280 for_each_lru(lru) {
281 pvec = &pvecs[lru - LRU_BASE];
282 if (pagevec_count(pvec))
283 ____pagevec_lru_add(pvec, lru);
284 }
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700285
286 pvec = &per_cpu(lru_rotate_pvecs, cpu);
287 if (pagevec_count(pvec)) {
288 unsigned long flags;
289
290 /* No harm done if a racing interrupt already did this */
291 local_irq_save(flags);
292 pagevec_move_tail(pvec);
293 local_irq_restore(flags);
294 }
Andrew Morton80bfed92006-01-06 00:11:14 -0800295}
296
297void lru_add_drain(void)
298{
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700299 drain_cpu_pagevecs(get_cpu());
Andrew Morton80bfed92006-01-06 00:11:14 -0800300 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301}
302
David Howellsc4028952006-11-22 14:57:56 +0000303static void lru_add_drain_per_cpu(struct work_struct *dummy)
Nick Piggin053837f2006-01-18 17:42:27 -0800304{
305 lru_add_drain();
306}
307
308/*
309 * Returns 0 for success
310 */
311int lru_add_drain_all(void)
312{
David Howellsc4028952006-11-22 14:57:56 +0000313 return schedule_on_each_cpu(lru_add_drain_per_cpu);
Nick Piggin053837f2006-01-18 17:42:27 -0800314}
315
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 * Batched page_cache_release(). Decrement the reference count on all the
318 * passed pages. If it fell to zero then remove the page from the LRU and
319 * free it.
320 *
321 * Avoid taking zone->lru_lock if possible, but if it is taken, retain it
322 * for the remainder of the operation.
323 *
Fernando Luis Vazquez Caoab33dc02008-07-29 22:33:40 -0700324 * The locking in this function is against shrink_inactive_list(): we recheck
325 * the page count inside the lock to see whether shrink_inactive_list()
326 * grabbed the page via the LRU. If it did, give up: shrink_inactive_list()
327 * will free it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 */
329void release_pages(struct page **pages, int nr, int cold)
330{
331 int i;
332 struct pagevec pages_to_free;
333 struct zone *zone = NULL;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700334 unsigned long uninitialized_var(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
336 pagevec_init(&pages_to_free, cold);
337 for (i = 0; i < nr; i++) {
338 struct page *page = pages[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
Nick Piggin8519fb32006-02-07 12:58:52 -0800340 if (unlikely(PageCompound(page))) {
341 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700342 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin8519fb32006-02-07 12:58:52 -0800343 zone = NULL;
344 }
345 put_compound_page(page);
346 continue;
347 }
348
Nick Pigginb5810032005-10-29 18:16:12 -0700349 if (!put_page_testzero(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 continue;
351
Nick Piggin46453a62006-03-22 00:07:58 -0800352 if (PageLRU(page)) {
353 struct zone *pagezone = page_zone(page);
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700354
Nick Piggin46453a62006-03-22 00:07:58 -0800355 if (pagezone != zone) {
356 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700357 spin_unlock_irqrestore(&zone->lru_lock,
358 flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800359 zone = pagezone;
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700360 spin_lock_irqsave(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 }
Nick Piggin725d7042006-09-25 23:30:55 -0700362 VM_BUG_ON(!PageLRU(page));
Nick Piggin67453912006-03-22 00:08:00 -0800363 __ClearPageLRU(page);
Nick Piggin46453a62006-03-22 00:07:58 -0800364 del_page_from_lru(zone, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 }
Nick Piggin46453a62006-03-22 00:07:58 -0800366
367 if (!pagevec_add(&pages_to_free, page)) {
368 if (zone) {
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700369 spin_unlock_irqrestore(&zone->lru_lock, flags);
Nick Piggin46453a62006-03-22 00:07:58 -0800370 zone = NULL;
371 }
372 __pagevec_free(&pages_to_free);
373 pagevec_reinit(&pages_to_free);
374 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 }
376 if (zone)
Hisashi Hifumi902aaed2007-10-16 01:24:52 -0700377 spin_unlock_irqrestore(&zone->lru_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378
379 pagevec_free(&pages_to_free);
380}
381
382/*
383 * The pages which we're about to release may be in the deferred lru-addition
384 * queues. That would prevent them from really being freed right now. That's
385 * OK from a correctness point of view but is inefficient - those pages may be
386 * cache-warm and we want to give them back to the page allocator ASAP.
387 *
388 * So __pagevec_release() will drain those queues here. __pagevec_lru_add()
389 * and __pagevec_lru_add_active() call release_pages() directly to avoid
390 * mutual recursion.
391 */
392void __pagevec_release(struct pagevec *pvec)
393{
394 lru_add_drain();
395 release_pages(pvec->pages, pagevec_count(pvec), pvec->cold);
396 pagevec_reinit(pvec);
397}
398
Steve French7f285702005-11-01 10:22:55 -0800399EXPORT_SYMBOL(__pagevec_release);
400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 * Add the passed pages to the LRU, then drop the caller's refcount
403 * on them. Reinitialises the caller's pagevec.
404 */
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700405void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406{
407 int i;
408 struct zone *zone = NULL;
KOSAKI Motohiro6e901572009-01-07 18:08:15 -0800409
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700410 VM_BUG_ON(is_unevictable_lru(lru));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
412 for (i = 0; i < pagevec_count(pvec); i++) {
413 struct page *page = pvec->pages[i];
414 struct zone *pagezone = page_zone(page);
Rik van Riel9ff473b2008-12-02 10:31:52 -0800415 int file;
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800416 int active;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
418 if (pagezone != zone) {
419 if (zone)
420 spin_unlock_irq(&zone->lru_lock);
421 zone = pagezone;
422 spin_lock_irq(&zone->lru_lock);
423 }
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700424 VM_BUG_ON(PageActive(page));
425 VM_BUG_ON(PageUnevictable(page));
Nick Piggin725d7042006-09-25 23:30:55 -0700426 VM_BUG_ON(PageLRU(page));
Nick Piggin8d438f92006-03-22 00:07:59 -0800427 SetPageLRU(page);
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800428 active = is_active_lru(lru);
Rik van Riel9ff473b2008-12-02 10:31:52 -0800429 file = is_file_lru(lru);
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800430 if (active)
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700431 SetPageActive(page);
KOSAKI Motohiro3e2f41f2009-01-07 18:08:20 -0800432 update_page_reclaim_stat(zone, page, file, active);
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700433 add_page_to_lru_list(zone, page, lru);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 }
435 if (zone)
436 spin_unlock_irq(&zone->lru_lock);
437 release_pages(pvec->pages, pvec->nr, pvec->cold);
438 pagevec_reinit(pvec);
439}
440
KOSAKI Motohirof04e9eb2008-10-18 20:26:19 -0700441EXPORT_SYMBOL(____pagevec_lru_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442
443/*
444 * Try to drop buffers from the pages in a pagevec
445 */
446void pagevec_strip(struct pagevec *pvec)
447{
448 int i;
449
450 for (i = 0; i < pagevec_count(pvec); i++) {
451 struct page *page = pvec->pages[i];
452
David Howells266cf652009-04-03 16:42:36 +0100453 if (page_has_private(page) && trylock_page(page)) {
454 if (page_has_private(page))
Christoph Lameter5b40dc72006-03-16 23:04:07 -0800455 try_to_release_page(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 unlock_page(page);
457 }
458 }
459}
460
461/**
462 * pagevec_lookup - gang pagecache lookup
463 * @pvec: Where the resulting pages are placed
464 * @mapping: The address_space to search
465 * @start: The starting page index
466 * @nr_pages: The maximum number of pages
467 *
468 * pagevec_lookup() will search for and return a group of up to @nr_pages pages
469 * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a
470 * reference against the pages in @pvec.
471 *
472 * The search returns a group of mapping-contiguous pages with ascending
473 * indexes. There may be holes in the indices due to not-present pages.
474 *
475 * pagevec_lookup() returns the number of pages which were found.
476 */
477unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
478 pgoff_t start, unsigned nr_pages)
479{
480 pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
481 return pagevec_count(pvec);
482}
483
Christoph Hellwig78539fd2006-01-11 20:47:41 +1100484EXPORT_SYMBOL(pagevec_lookup);
485
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
487 pgoff_t *index, int tag, unsigned nr_pages)
488{
489 pvec->nr = find_get_pages_tag(mapping, index, tag,
490 nr_pages, pvec->pages);
491 return pagevec_count(pvec);
492}
493
Steve French7f285702005-11-01 10:22:55 -0800494EXPORT_SYMBOL(pagevec_lookup_tag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496/*
497 * Perform any setup for the swap system
498 */
499void __init swap_setup(void)
500{
Jan Beulich44813742009-09-21 17:03:05 -0700501 unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700503#ifdef CONFIG_SWAP
504 bdi_init(swapper_space.backing_dev_info);
505#endif
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 /* Use a smaller cluster for small-memory machines */
508 if (megs < 16)
509 page_cluster = 2;
510 else
511 page_cluster = 3;
512 /*
513 * Right now other parts of the system means that we
514 * _really_ don't want to cluster much more
515 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516}